AC clutch fuse blowing

MK2 GTO TT

A while back the 10a fuse would blow when engaging the AC, so did a little troubleshooting and found the circuit was pretty much open on the magnetic ring (not sure the proper terminology) so i got a junk compressor and swapped it out and it was working happily for the last year or 2 but now its happened again. Now before i go off and get another im wondering if this is a coincidence or a symptom of something else that might not be quite right? any ideas?
Tempted to buy a new whole clutch assemble from evil empire (unless theirs a way of just buying a suitable ring?) but dont really want to do that then find that also dies in another year or so.
thanks